Pharmaceutics - Transdermal

Question 1

What is known as “Flip-Flop” kinetics?

Answer 1

When the kinetics of absorption is slower than that of elimination

Question 2

What are the benefits of transdermal drug delivery?

Answer 2

Avoids first-pass effect

Maintains drug levels in the therapeutic window for longer

Improved patient compliance due to less dosing times

Drug can be stopped simply by removing the patch

Question 3

What are the negatives of transdermal drug delivery?

Answer 3

Limited to potent drugs (Usually a daily dose of less than 50mg)

Drugs need to be fairly lipophillic and small

The area of the patch means only so much drug can fit into it! (usually less than 100cm2)

Can be irritating or sensitising

Question 4

Currently, how many drugs can be administered using a patch?

Answer 4

17

Question 5

What’s the difference between a single-layer and bi-layer transdermal system?

Answer 5

Bi-layer –> There is a polymetric matrix layer that contains the drug as well as an adhesive layer that contains the drug

Question 6

How do we calculate the flux or area of a patch when we have other mathmatical information?

Answer 6